Interesting. I would guess that any Utah judge could easily point to the recent U.S. Supreme Court ruling on “gay marriage” and accept that as the explicit consent of the Federal government for anything that anyone decides constitutes a marriage.
Even the Utah Attorney General's website states: "Polygamy is illegal in Utah and forbidden by the Arizona constitution. However, law enforcement agencies in both states have decided to focus on crimes within polygamous communities that involve child abuse, domestic violence and fraud."
There are an estimated 40,000 polygamists in the intermountain west.